Carlo reale



. C. REALE. MEANS FOR SCAVENGING CYLINDERS 0F TWO-STROKE CYCLE COMBUSTION ENGINES.

. APPLICATION FILED JAN-31,1919. 1,321,392.

Patented N 0v. 11, 1919.

' ually increased and the value CARLO REALE, 0F GENOA, ITALY.

MEANS FOR SCAVENGING CYLINDERS Specification of Letters Patent.

01 TWO-STROKE-CYCLE COMBUSTION-ENGINES.

Patented Nov. 11, 1919.

Application filed January 31, 1919. Serial No. 274,353.

To all whom it may concern:

Be it known that I, CARLO REALE, subject of the King of Italy, and resident of Genoa, Italy, have invented certain new and useful Improvements in Means for scavenging Cylinders of Two-Stroke-Cycle Combustion- Engines,"of which the following is a specification.

This invention has for its object an arrangement by means of which scavenging of cylinders and supply of air thereto in two stroke cycle engines are obtained in an automatic manner without requiring moving parts or members.

The annexed drawing shows by Way of example an embodiment of the arrangement according to thisinvention, and

Figure 1 is a sectional diagrammatic view of a two stroke cycle combustion engine cylinder;

Fig. 2 shows the working diagram of the same cylinder, and

Fig. 3 shows the distribution diagram.

As shown by Fig. -1, the wall of the cylinder 1 is provided with two ports (or series of ports) 3 and 4 located opposite to exhaust port 2; said ports 3 and 4 are displaced to each other lengthwise of the cylinder and independent from each other, port 3 opening into a receiver 5 and port 4 opening into a receiver 6 which is the scavenging air tank and communicates with receiver 5 through an opening controlled by an automatic valve 7.

Ports 3' and 4 are located in such a position with regard to exhaust port 2 that the piston during its downward stroke clears port 3 before port 2 and clears port 4 after port 2 has been cleared to a given extent, say about to a half of its length.-

When the piston, during its downward stroke reaches the position P shown in Fig. 1, port 3 is beginning to clear but as the pressure existing in the cylinder is considerably greater than that existing :in the tank 6, valve 7 is prevented from opening, the same being adapted to open inwardly into receiver 5.

On piston reaching the position P exhaust port 2 is beginning to clear and the pressure in the cylinder is becoming reduced, the cleared area of the port 2 being gradof said pressure becomes finally lower than the pressure of the scavenging air in the receiver 6.

At such a time valve 7 is opened by the pressure in tank 6 and the air contained therein enters the cylinder through port 3 and, on the piston reaching the position P also port 4 is beginning to clear, the air being thus fed into the cylinder through all ports and scavenging being improved.

The scavenging air pressure is greatest and therefore the opening of valve 7 takes place before the exhaust is completed, the scavenging air pressure having a value of about kg. 0.3-0.4, greater than that of the exhaust gases, this pressure being about kg. 0.07-0.09.

By the described arrangement of ports 3 and 4 the scavenging period is continued also after the piston, during its upward stroke, has reached the position P, and covers port 4, said period being completed on exhaust port 2 being closed (position P of piston).

Then air supply period begins, this supply continuing through port 3 until pressures existing in the cylinder 1 and tank 6 respectively are balanced, as at that time valve 7 is automatically closed by its own weight.

Thereafter the piston efi'ects compression, the cycle being completed by fuel injecting and expansion periods as shown by diagrams of Figs. 2 and 3.

The described arrangement may be modified in various manners without departing from the invention; by way of example one or more shutting members operating automaticall may be used, the same being either arrange directly at the scavenging ports or connected with them through a passage.

Further, valves or other automatic shutting means may be provided onl at the passage of ports 3, or they may be provided separately both to passages of ports 3 and ports 4, or finally said means may be rovided at a single passage common to goth scavenging ports or series .of ports.

In any case, the cylinder scavenging is obtained without necessity for any moving part so that construction and adjustment of engine are made more easy, particularly in the case of reversible engines, the operation of the engine being also more regular and economical and the efficiency of the same being improved owing to the mproved charactors of the cycle.

1. In two stroke cycle combustion engines,

a cylinder, a piston reciprocating therein, exhaust ports in the walls of said cylinder, a plurality of scavenging ports opening in the walls of the cylinder one of which has such a position as to be cleared by the piston before the exhaust ports and another has such a position as to be clearedafter the exhaust ports, a scavenging air receiver communicating with the cylinder through said scavenging ports and automatic means controlling the communications through the first cleared scavenging ports.

2. In two stroke cycle combustion engines, a cylinder, a piston reciprocating therein, exhaust ports in the walls of said cylinder, a scavenging port opening in the wall of the cylinder in such a position as to be cleared by the piston before the exhaust ports and a scavenging port opening in the wall of the cylinder in such a position as to be cleared by the piston after the exhaust ports, a scavenging air receiver communicating directly with the second named scavenging port, a chamber communicating with the first named scavenging port and with the receiver, the communication between said chamber and the receiver being controlled by automatically acting means.

3. In two stroke cycle combustion engines, a cylinder, a piston reciprocating therein, exhaust ports in the walls of said cylinder, a scavenging-port opening in the wall of the cylinder in such a position as to be cleared by the piston before the exhaust port and a scavenging port opening in the wall of the cylinder in such a position as to be cleared by the piston after the exhaust ports, a scavenging air receiver communicating directly with the second named scavenging port, a chamber communicating with the first named scavenging port and With the receiver, the communication between said chamber and the receiver being controlled by automatically acting means.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses:

W. P. SHOCKLEY, HOWARD H. HALL. 

